Numerous antibiotic compositions are known, some exhibiting antibiotic activity against a broad spectrum of microorganisms, and others exhibiting antibiotic activity only against one or a few narrow classes of organisms, such as gram-positive bacteria. One shortcoming associated with all known antibiotics is that microorganisms, especially bacteria, can become resistant to an antibiotic to which they were previously susceptible under certain conditions. Human pathogens are among the microorganisms which are capable of developing antibiotic resistance. Thus, even though certain antibiotics are highly efficacious against a broad range of microorganisms, it is necessary to continually develop new antibiotic compositions in order to remain ahead of the development of antibiotic-resistant microorganisms or to develop antibiotics that are, due to their intrinsic characteristics of antimicrobial action, less likely to generate resistant strains. Further, the continuing identification of new antibiotics will reduce the likelihood that a strain of microorganism will arise which is resistant to most or all known antibiotics.
Bacterial resistance to antibiotics is an increasing problem of potentially pandemic proportions, both in the United States and abroad. In one review, more than 31% of 17,000 bacterial isolates of Streptococcus pneumoniae obtained from patients were identified as being resistant to penicillin. Furthermore, in 1997, three untreatable vancomycin-resistant cases were reported in Camden, N.J. (Murray, 1977, Am. J. Med. 102:284-293).
The need for anti-microbial products has increased in the past few years, due to the emergence of multi-drug resistant bacterial infections. The U.S. Centers for Disease Control and Prevention estimate that antibiotics are one of the most widely used classes of drugs, both in the United States and world-wide. Extensive research efforts are underway to identify potential antibiotic candidate compounds. The present invention satisfies the continuing need for new antibiotic compositions.